[tz] Uruguay out of DST

Lester Caine lester at lsces.co.uk
Sun Jul 12 08:15:33 UTC 2015

On 12/07/15 03:36, Guy Harris wrote:
>> It's not just ICU.  There are dozens of software frameworks and libraries that depend on tzdata
> Presumably meaning "depend on their own copies of tzdata" (perhaps because they have to run on OSes that don't ship with tzdata, e.g. Windows and some versions of UN*X or, at least, older releases of those versions).  ("date" depends, indirectly, on tzdata, but it doesn't ship with its own copy. :-))
> If there are other reasons for maintaining their own copies of tzdata, perhaps improvements to the UN*X time APIs could help.

One aspect of all of this which keeps getting totally ignored is that
data normalized using a particular set of tz rules needs to be processed
with those rules before applying the CURRENT rules. One aspect of tzdist
is that most people only expect a CURRENT set of tz rules and ignore
that the information may not have been generated with those rules. The
WAY of processing this material needs a proper overhaul and tzdist HAS
the means of establishing if a piece of material may be subject to a
change. This may be looking at an historic set of date ( for which
pre-1970 rules may be important ) but even with current data as has
already been stated here. If the diary for next year has been published
using 'version a' then yes at some point that published data needs
updating, but until that happens CURRENTLY one just gets duff data,
while proper use of tzdist would flag that perhaps the meeting you are
planning to go to may be an hour an hour adrift now.

The major problem today is that much historic data has been created with
the tzdata rules of that time but with no reference to just what those
rules were, and so may well be inaccurate. So we need to get tzdist
running with a single reliable data source, complete with all of it's
history and then rebuild the rest of the infrastructure to respect that
process. The Uruguay data would have been published by now, and diaries
for next year that may be affected by the change would at least flag a
potential difference.

Lester Caine - G8HFL
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

More information about the tz mailing list